Conventionally, devices such as televisions, PC monitors, mobile phones, smart phones, portable game devices, tablet devices, wearable devices and automotive monitors, among others, have used a liquid crystal display device or an organic EL panel as a display means. In recent years, in such display devices, in view of finer pitches and thinner and lighter devices, mounting of driver ICs directly onto glass substrates of display panels, which is known as COG (chip on glass), has been employed.
For example, in a liquid crystal display panel in which COG mounting is employed, as shown in FIG. 12A and FIG. 12B, a plurality of transparent electrodes 102 made from, among other materials, ITO (indium tin oxide), are formed onto a transparent substrate 101 made from, for example, a glass substrate, and an electronic component such as a liquid crystal driver IC 103 is connected onto these transparent electrodes 102. The liquid crystal driver IC 103 has electrode terminals 104 corresponding to the transparent electrodes 102 formed onto the mounting surface thereof and is thermocompression-bonded onto the transparent substrate 101 via an anisotropic conductive film 105, thereby connecting the electrode terminals 104 to the transparent electrodes 102.
The anisotropic conductive film 105 contains a binder resin into which conductive particles are dispersed and is film-formed, and by being thermocompression-bonded between two conductors, electrical conduction between the conductors is achieved by the conductive particles and mechanical connection between the conductors is ensured between the conductors by the binder resin. The adhesive agent constituting the anisotropic conductive film 105, although typically a highly reliable thermosetting binder resin is used, may be a photosetting binder resin or a thermo/photosetting binder resin.
In the case of connecting the liquid crystal driver IC 103 to the transparent electrodes 102 via such an anisotropic conductive film 105, the anisotropic conductive film 105 is first temporarily bonded onto the transparent electrodes 102 of the transparent substrate 101 by a temporary pressure bonding means which is not illustrated in the drawings. After mounting the liquid crystal driver IC 103 onto the transparent substrate 101 via the anisotropic conductive film 105 to form a temporary connection body, a thermocompression bonding means, for example, a thermocompression bonding head 106, is used to hot-press the liquid crystal driver IC 103 along with the anisotropic conductive film 105 towards the transparent substrate 102. Heat applied by the thermocompression bonding head 106 causes a thermosetting reaction in the anisotropic conductive film 105, thereby connecting the liquid crystal driver IC 103 onto the transparent electrodes 102.